• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.353-369
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• 2000

We systematized an stratified spatial sample design(SSSD) that uses the adequate stratification criteria such as the shapeness or the dispersion of an interesting region in a spatial population. And we proposed an adaptive searching estimation method in the SSSD to estimate the area of region of interest in two-dimensional surfaces. When wc adopt the proposed adaptive searching estimation method in SSSD, the observing sample size is more decreased than a classical sample design that all the designed sample size is observed. Nevertheless it has been shown that we can produce the moderate result but the efficiency is a slight reduced.

• The Korean Journal of Applied Statistics
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• v.9 no.2
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• pp.145-159
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• 1996

We propose an adaptive searching method using some spatial relations among sample points to estimate the interesting area in the spatial population. The fundamental idea is to observe the neighboring sample points when a sample point is satified with some condition of an adaptive searching observation. For obseving the sample points with this method to estimate the area the sample size is decreased. From this result, we may expect to reduce the cost and time consuming in observation the sample points and to draw the shape of the interesting area without prior information of an spatial population. Some analytical simulation results are also presented.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.501-504
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• 2005

블록 정합 기법(block matching algorithm, BMA) 중에서 가장 널리 알려진 3 단계 탐색(three-step search, 3SS) 알고리즘은 큰 움직임 추정에 적합하지만 고정된 탐색 점으로 인하여 작은 움직임 추정에는 계산 면에서 낭비가 심하고 탐색이 잘못될 경우가 대부분이다. 한편, 효율적인 3 단계 탐색(efficient three-step search, E3SS)은 중앙-편중된 움직임 추정을 작은 다이아몬드 탐색(small diamond search, SDS) 알고리즘으로 보완하여 예측성과 탐색 속도를 향상시킨 알고리즘이다. 본 논문에서는 탐색 초기 단계에서 탐색 점을 최적 배치하고 E3SS 의 SDS 알고리즘을 변형시킨 탐색 알고리즘을 제안한다. 실험 결과는 제안된 탐색 알고리즘이 E3SS 와 비교하여 평균 22% 정도 계산량을 감소시키면서도 MSE(Mean Square Error)의 성능 저하를 거의 보이지 않는 것으로 나타난다.

• Journal of Broadcast Engineering
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• v.3 no.1
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• pp.85-92
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• 1998

The block matching algorithm is the most popular motion estimation method in image sequence coding. In this paper, we propose a VLSI architecture. for implementing a recently proposed fast bolck matching algorith, which uses spatial correlation of motion vectors and hierarchical searching scheme. The proposed architecture consists of a basic searching unit based on a systolic array and two shift register arrays. And it covers a search range of -32~ +31. By using the basic searching unit repeatedly, it reduces the number of gatyes for implementation. For basic searching unit implementation, a proper systolic array can be selected among various conventional ones by trading-off between speed and hardware cost. In this paper, a structure is selected as the basic searching unit so that the hardware cost can be minimized. The proposed overall architecture is fast enough for low bit-rate applications (frame size of $352{\times}288$, 3Oframes/sec) and can be implemented by less than 20,000 gates. Moreover, by simply modifying the basic searching unit, the architecture can be used for the higher bit-rate application of the frame size of $720{\times}480$ and 30 frames/sec.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.9-12
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• 1998

본 논문에서는 좌·우영상의 차영상 정보를 이용하여 3차원 입체영상의 변이(disparity)를 추정함에 있어서 계산량을 줄이는 변이 추정 방법을 제안하였다. 3차원 입체 영상의 변이를 블록 기반으로 추정하는 방법으로는 전체 탐색(Full Search)알고리듬이 있으나 탐색범위 안에 존재하는 모든 위치에 대하여 추정 오차를 계산하기 때문에 많은 계산량을 줄이기 위한 변이 추정 기술이 많이 연구되고 있다. 그러나 일반적으로 전체 탐색 알고리듬 보다 많은 화질열화를 초래한다. 본 논문에서 제안한 방법은 좌·우영상의 차영상을 이용하여 차영상의 블록 특성에 따라 추정하고자 하는 블록들을 분류하여 각각 그 특성에 맞는 적합한 탐색범위를 가지고 변이 추정방식 과정을 수행한다. 본 논문에서 제안한 변이 추정하는 기술은 기존의 변이 추정 기법들에 비하여 화질의 열화가 적으면서 계산량을 줄이는 결과를 보여준다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.586-590
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• 2006

본 논문에서는 다이아몬드 탐색(diamond search, DS)과 효율적인 3 단계 탐색(efficient three-step search, E3SS) 등의 블록 정합 기법(block matching algorithm, BMA)들에서 이용된 작은 다이아몬드(small diamond) 패턴을 광역 탐색에 적합하도록 확장시킨 고속의 움직임 추정 알고리즘을 제안한다. 제안된 알고리즘에서는 탐색 윈도우(search window)의 중앙으로부터 설치된 정사각형 패턴의 크기가 내부에서 대수적으로 감소되며 작은 다이아몬드 탐색(small diamond search, SDS) 기법에 의해 탐색이 완료된다. 실험 결과는 제안된 알고리즘이 DS 보다 평균 3개의 탐색 점을 더 적게 사용하고 E3SS에 비하여 약 5개 정도의 탐색 점 수에 대한 이득을 보이지만 움직임 추정상의 정확도는 다른 고속 BMA들과 거의 동일한 수준을 유지하는 것으로 확인된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.594-600
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• 2017

This paper proposes a global search based motion estimation algorithm for high performance HEVC encoder and its hardware architecture. To eliminate temporal redundancy, motion estimation in HEVC inter-view prediction uses global search and fast search algorithm to search for a predicted block having a high correlation with the current PU in an interpolated reference picture. The global search method predicts the motion of all candidate blocks in a given search area, thus ensuring optimal results, but has a disadvantage of large computation time. Therefore we propose a new algorithm that reduces computational complexity by reusing SAD operation in global search to reduce computation time of inter prediction. As a result of applying the proposed algorithm to standard software HM16.12, the computation time was reduced by 61%, BDBitrate by 11.81%, and BDPSNR by about 0.5% compared with the existing search algorithm. As a result of hardware design, the maximum operating frequency is 255 MHz and the total number of gates is 65.1K.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.3
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• pp.18-27
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• 2009

In this paper, we propose a frame rate conversion algorithm using adaptive search-based motion estimation (ME). The proposed ME method uses recursive search, 3-step search, and single predicted search as candidates for search strategy. The best method among the three candidates is adaptively selected on a block basis according to the predicted motion type. The adaptation of the search method improves the accuracy of the estimated motion vectors while curbing the increase of computational load. To support the proposed ME method, an entire image is divided into three regions with different motion types. Experimental results show that the proposed FRC method achieves better image quality than existing algorithms in both subjective and objective measures.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.418-423
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• 2004

The motion estimation algorithm based block matching is a widely used in the international standards related to video compression, such as the MPEG series and H.26x series. Full search algorithm(FA) ones of this block matching algorithms is usually impractical because of the large number of computations required for large search region. Fast search algorithms and conventional binary block matching algorithms reduce computational complexity and data processing time but this algorithms have disadvantages that is less performance than full search algorithm. This paper presents new Boolean matching algorithm, called BCBM(Bit Converted Boolean Matching). Proposed algorithm has performance closed to the FA by Boolean only block matching that may be very efficiently implemented in hardware for real time video communication. Simulation results show that the PSNR of the proposed algorithm is about 0.08㏈ loss than FA but is about 0.96∼2.02㏈ gain than fast search algorithm and conventional Boolean matching algorithm.

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.71-82
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• 2012

Some previous studies adopted a method statistically based on the observed traffic volumes and travel times to estimate the parameters. Others tried to find an optimal set of parameters to minimize the gap between the observed and estimated traffic volumes using, for instance, a combined optimization model with a traffic assignment model. The latter is frequently used in a large-scale network that has a capability to find a set of optimal parameter values, but its appropriateness has never been demonstrated. Thus, we developed a methodology to estimate a set of parameter values of BPR(Bureau of Public Road) function using Harmony Search (HS) method. HS was developed in early 2000, and is a global search method proven to be superior to other global search methods (e.g. Genetic Algorithm or Tabu search). However, it has rarely been adopted in transportation research arena yet. The HS based transportation network calibration algorithm developed in this study is tested using a grid network, and its outcomes are compared to those from incremental method (Incre) and Golden Section (GS) method. It is found that the HS algorithm outperforms Incre and GS for copying the given observed link traffic counts, and it is also pointed out that the popular optimal network calibration techniques based on an objective function of traffic volume replication are lacking the capability to find appropriate free flow travel speed and ${\alpha}$ value.